Printing ink and method of making the same



Patented Jan. 2, 1951 [TE-D -BRINTINGJNKYAND ME mon-oE-MAKING THE SAME Vincent A-'."Lai1diei'man, Hamilton; Ohio; assignor td'flhe vhampion Papeniand Fibrfiompa'ny, iHamiltom Ohio; a eorporationi of Ohio 6 Drawing. .O riginal application luly 10.31945,

SeriaFNofib'OlfiOl. Divided and. this. application Marchf3flj'l949, SerialTNl8'4'A90 4 G-Glaims. (Cl T406324) "added *and the whole massis put through 'an ink i. This inventiorr-relates' toprinting 'inks and .:.;moreparticularly concerns -an-im proved waterbase ii'ik for useon printing presses.

Thepro'perties generallydesired in 'letter'mress as 'ei'ein employedforms an excellent base -for -inksinclude -hightinctor-ial-values, good-wetting; e-' 'the*-'other*= ingredients Lofthe ink. Itprevents "spreading and transfer properties on thepress, livering of the ink, a condition Which-comand stability in the sense ofavoidi-ng bacterial monly occurs when either ingredient alone is decomposition;hardening, liveringj settling-out usedimwater-base inks. -It disperses most pigduring"storagefetc. "Prior to the-present'invennents more per-iectly; than -either agentalone tiong -the'only available printing inks combining: l0- rand it' ,firmly bonds the pigment to the paper. "-these propertiesto'the'desired-de'gree havebeen @Moreover -it appears to bring about a perfect a stability as well as wetting, spreading, transfere' 1 ring and dispersing properties comparable 1th the better grades of 'oilbaseletter-press "inks.

Another object of the inventionisto provide a water-base ink capable' of --forming solid coverblending-. of the urea andhyg-roscopic agent to i -p ;oduce. a homogeneous vehicle excellently dapted-ior the incorporation of a wide variety :known pigments.

Although;casein..'inks=.-are notoriously prone to acterialrispoilage; the presence; of the natural e sin 4 renders these inks; permanently stable. therprotein adhesives-- such as soy bean-proages in deep colors and at thesam'e time-ca e ZO Qteinmay .be substituted-for.-the casein in many 'pable of printing fine halt tones without' sq'uash- .1 ng and. filling up. A further objectof thef'in- -ve'ntion is to provideawater -base inkcontainln casein or an equivalent protein -hdhe'sive --which will keep-indefinitely-w ithout spoilage,

I The objects of the invention also-include a method for preparing a -'water-bas'e =ink of the character-indicated. -Other objects will be apparent from the following description.

5; and other-propertiesdesired for any given; re-

cases. ,7 The relative proportions of pigment, natural ,resin; and pr-otein'adhesive to be used may vary -overa wide range depending onthe particular igment andresin employed; thetack,- consi sten quirement. Thus I have obtained- -satisfactory results usin from 3 to 40 parts of casein and ...-.f-rom 3 to-luil partsof'rosin per- 100 parts of pig- The preferred inksof the present inventiontggg menta tbyweight).

are essentially alkaline casein-rosin dispersions of "an insoluble pigment in an aqueous (solution of urea, usually containing a suitable hygroscopic agent which may be a polyhydric alcohol such If desireda suitable soap, 1e. g.-,- sodium oleate -,may; be incorporated into the ink,

' 'I hexureaor equivalent substance is an .essen- 'itial ingredient since in combination with the as ethylene glycol, glycerine, sorbitol or=the=likeie caseinand: naturalresin-it greatly improves the In place of the rosin,- .other-na'turally occurring resinous materials may-be-empl0yed1 such as wetting; .spreading -,ancl a transfer properties of the ink on the press and thus enables a more .Sshellac, damar, copal, sandarac, andr-the. =like, perfectiapplicationofthe ink-tethesurfa-ce to but in general, rosin, either-assuchi or :as} ester beprinted. O'rdinarily from 2:to itimesasmuch gum-or as a modified rosin; is'most satisfactorylt: mureaa as rcasein is used, but somewhatlarger: or -,,F0r convenience I ,willherein designatethevariesmallerh amou-nts can -sometimes be employed. bus-resinous ingr d s his sort asfnatllral llhewotal solids off-theinkmay be variediover resins. .sacfairlyz'wide range, depending "on: the particular In preparing these inks, it is advantageous to consistency most desired for any particular job. first heat the natural resin and the hygroscopic I have obtained good results with inks of from agent, e. g. ethylene glycol, until the natural resin, e. g. rosin is melted. To this solution is added a solution of caustic soda or other alkali. A casein solution made by dissolving casein in alkali is prepared and the natural resin and casein solutions are mixed together. Ordinarily, the amount of natural resin employed is considerably in excess of the casein. To the mixed solutions is added urea in large excess over the 54% to 83% total solids. These inks have the consistency of thicker or thinner pastes just as in the case of oil base letter-press inks. If desired a much thinner ink suitable for rotogravure printing may be prepared by reducing the total solids to any required degree.

My improved inks always show an alkaline reaction, commonly having a pH of from about 7.0 to about 9.0. Above a pH of 9.0 there is a amount of casein used. Finally a pigment is 55 tendency for the natural resin to separate out from the ink. It has been my experience that inks of this type commonly have optimum wetting and transfer properties at a pH of about 8.5 with most pigments.

Certain examples of inks embodying the invention and the process of preparing such inks will now be given.

Example 1 solved. One hundred grams of tungstated Victoria Blue toner were then added and the whole mixture thoroughly incorporated in an ink mill. This ink had a pH of 8.3 and had a consistency of good letter press printing ink. It behaved very well on the printing press and gave excellent printing results.

Example 2 Sixty grams of water white rosin, 30 grams of oleic acid, and 54 grams of ethylene glycol were heated together. of sodium hydroxide were added. A casein solution was prepared by warming 25 grams of casein, 5 grams of water, and 3 grams of a 33 927 solution of sodium hydroxide. The two solutions were then mixed and 67.5 grams urea were stirred in. Then 200 grams of Para Red pigment were thoroughly incorporated in the mixture by means of an inkmill. This ink had a pH of 8.4 and had the consistency of a good letter-press printing ink. It handled well on the printing press and printed excellently.

It will be understood that the invention is not limited to the details of the foregoing examples except insofar as recited in the appended claims.

This application is a division of my copending applicationSer. No. 604,301, filed July 10, 1945, now Patent No. 2,468,633.

I claim: 1 H

1. A water-base printing ink having the consistency of letter-press oil-base ink consisting, in parts by weight, of 100 parts of pigment dispersed in an alkaline aqueous vehicle comprising from about 3 to 40 parts of an alkali-di'spersible protein, from about 3 to 100 parts of a natural resin, and urea in an amount from about 2 to 7 times the amount of protein, said ink having a pH of from 7 to 9.

2. A water-base printing ink having the consistency of letter-press oil-base ink consisting, in parts by weight, of 100 parts of pigment dispersed in an aqueous alkaline vehicle comprising from about 3 to 40 parts of casein, from about 3 to 100 parts of a natural resin, a polyhydric alcohol,

Then cc. of a 50% solution 4 and urea in an amount from about 2 to 7 times the amount of casein, said ink having a pH from about 7 to 9.

3. A Water-base printing ink having good spreading and transfer properties consisting, in parts by weight, of 100 parts of pigment dispersed in an aqueous alkaline vehicle comprising from about 3 to parts of casein, from about 3 to 100 parts of rosin, ethylene glycol, and urea in an amount from about 2 to 7 times the amount of casein, said ink being of the consistency of a paste and having a pH of about 8.5.

4. A water-base printing ink having the con- .sistency of letter-press oil-base ink consisting, in

parts by Weight, of 100 parts of pigment dispersed in an aqueous alkaline vehicle comprising from about 3 to 40 parts of casein, from about 3 to 100 parts of rosin, a soap, ethylene glycol, and urea in an amount from about 2 to '7 times the amount of casein, said ink having a pH of about 8.5.

5. A process of preparing a printing ink which comprises heating together from about 3 to 100 parts of a natural resin and about an equal amount of a polyhydric alcohol until said resin dissolves in said alcohol, adding an alkali thereto, dissolving from about 3 to 40 parts of an alkalidispersible protein with alkali to form an aqueous alkaline solution, mixing the two solutions together, adding urea thereto in an amount from about 2 to 7 times the amount of protein, and thereafter dispersing 100 parts of pigment in the mixture, the amount of alkali added in toto being sufiicient to impart to the ink a pH of from 7 to 9.

6. A process of preparing a Water-base prin ing ink which comprises heating together from about 3 tolOO parts of rosin and about an equal amount of ethylene glycol until the rosin dissolves in the glycol, adding an alkali thereto, dissolving from about 3 to 40 parts of casein with alkali to form an aqueous alkaline casein solution, mixing the two solutions together, adding urea thereto in an amount from about 2 to 7 times the amount of casein, and thereafter dispersing 100 parts of pigment in the mixture, the amount of I alkali added in toto being sufficient to impart to the ink 21. pH of from 7 to 9.

VINCENT A. LAUDERMAN.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Certificate of Correction Patent No. 2,536,555 January 2, 1951 VINCENT A. LAUDERMAN It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 3, line 33, for 5 grams read 54 grams; column 4, line 57 list of references cited, for patent number 1,621,532 read 1,621,542;

and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the ease in the Patent Oflice.

Signed and sealed this 20th day of March, A. D. 1951.

THOMAS F. MURPHY,

Assistant Commissioner of Patents. 

1. A WATER-BASE PRINTING INK HAVING THE CONSISTENCY OF LETTER-PRESS OIL-BASE INK CONSISTING, IN PARTS BY WEIGHT, OF 100 PARTS OF PIGMENT DISPERSED IN AN ALKALINE AQUEOUS VEHICLE COMPRISING FROM ABOUT 3 TO 40 PARTS OF AN ALKALI-DISPERSIBLE PROTEIN, FROM ABOUT 3 TO 100 PARTS OF A NATURAL RESIN, AND UREA IN AN AMOUNT FROM ABOUT 2 TO 7 TIMES THE AMOUNT OF PROTEIN, SAID INK HAVING A PH OF FROM 7 TO
 9. 